<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        a:link{
            color:red;
        }
        a:visited{
            color:green;
        }
        a:hover{
            color:blue;
            font-size: 30px;
        }
        a:active{
            color:yellow;
        }
    </style>
</head>
<body>

  <a href="#">百度</a>
</body>
</html>